Portable data collection devices are widely used in the manufacturing, service and package delivery industries to perform a variety of on-site data collection activities. Such portable data collection devices often include integrated bar code dataform readers adapted to read bar code dataforms affixed to products, product packaging and/or containers in warehouses, retail stores, shipping terminals, etc. for inventory control, tracking, production control and expediting, quality assurance and other purposes.
Bar code dataforms come in a variety of different formats including one and two dimensional bar codes, matrix codes and graphic codes, as well as words and numbers and other symbols, which may be printed or etched on paper, plastic cards and metallic and other items. For example, a one dimensional bar code dataform typically consists of a series of parallel light and dark rectangular areas of varying widths. The light areas are often referred to as “spaces” and the dark areas as “bars”. Different widths of bars and spaces define different characters in a particular bar code dataform.
Data originally encoded in a dataform is recovered for further use in a variety of ways. For example, a printed bar code may be illuminated to derive reflectance values which are digitized, stored in buffer memory and subsequently decoded to recover the data encoded in the bar code. The printed bar code may be illuminated using a laser, an array of LEDs, ambient light, or the like. The light reflected from the printed bar code typically is captured using a photosensor such as, for example, a CCD detector, CMOS detector, etc.
A problem associated with conventional dataform readers is power consumption. The reader devices are typically used for short periods of time, between which the units are inactive. Conventional handheld dataform readers typically include two major components housed within a plastic enclosure. A scan engine is provided for reading a dataform and encoding the data therefrom, and a host interface board is included for providing power to the scan engine and for communicating data from the scan engine to other devices, such as computers, modems, and/or transmitters. The scan engine and the interface are commonly separate circuit boards or modules, interfacing via one or more cables and/or connectors.
Many mobile or portable data collection devices are powered via batteries. In such battery powered devices, it is desirable to minimize the frequency of battery replacements or recharges. As such, minimizing power consumption is an important design consideration. Some conventional scan engine units include circuitry to implement a low power or sleep mode, which may be engaged based upon inactivity for a certain time period. However, in present designs, only the scan engine unit enters into a sleep mode, while the interface board circuitry power consumption continues. Accordingly, there remains a strong need for further reducing the power consumption of handheld data collection devices, with minimal cost increase and/or modification to the components thereof.